Bushing bypass

ABSTRACT

A bushing bypass. The bushing bypass includes a bushing having a top surface and a bottom surface. The bushing also includes an inner diameter surface extending between the top surface and the bottom surface. The bushing also includes an outer diameter surface extending between the top surface and the bottom surface. The bushing further includes a channel formed in the outer diameter surface. The channel extends from the top surface of the bushing to the bottom surface of the bushing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and claims priority to the U.S.patent application Ser. No. 16/659,148 filed on Oct. 21, 2019, entitled“BUSHING BYPASS” by Daniel McCormick et al., assigned to the assignee ofthe present application, having Attorney Docket No. FOX-0087US, and ishereby incorporated by reference in its entirety.

The application Ser. No. 16/659,148 claims the benefit of and claimspriority to the U.S. Provisional Patent Application No. 62/751,420 filedon Oct. 26, 2018, entitled “BUSHING BYPASS” by Daniel McCormick et al.,assigned to the assignee of the present application, having AttorneyDocket No. FOX-0087US.PRO, and is hereby incorporated by reference inits entirety.

FIELD OF THE INVENTION

Embodiments of the present technology relate generally to bushing and/ora fork leg in which the bushing is disposed.

BACKGROUND

In some fork assemblies such as, for example, bicycle or motorcycle forkassemblies, an upper fork leg is telescopically engaged with a lowerfork leg. Conventionally, one or more bushings are used to provide aslidable interface between the first fork leg and the second fork leg.The bushings are disposed within one of the fork legs such that theouter edge of each of the bushings abuts the inner diameter of the firstfork leg, and the inner diameter of each of the bushings abuts the outerdiameter of the second fork leg.

Because the bushings occupy the annular region between the first and thesecond fork legs, the bushings restrict the flow of gas or fluids pastthe bushings. This bushing-induced restriction will often generate apressure differential between one side or the other side of a bushing.Such a pressure differential is depicted in Prior Art FIG. 1. It will beunderstood that such a pressure differential is typically not desired,and that such a pressure differential is likely to be generated duringmotion of the first leg with respect to the second leg.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present invention are illustrated by way of example, andnot by way of limitation, in the accompanying drawings, wherein:

Prior Art FIG. 1 is a cut-away view of a conventional fork assembly inwhich the use of conventional bushings generates a pressure differentialbetween the conventional bushings

FIG. 2 is a perspective view of a bushing, in accordance with anembodiment of the present invention.

FIG. 3 is a perspective view of a fork leg, in accordance with anembodiment of the present invention.

FIG. 4 shows an embodiment having channels formed into the outerdiameter of a first bushing and channels are formed into the innerdiameter of the housing at the location where a second bushing isdisposed to reduce gas or fluid restriction at the location of firstbushing and second bushing, in accordance with an embodiment of thepresent invention.

FIG. 5 depicts an embodiment in which outer diameter channels of thebushing and the inner diameter channels of the housing are offset withrespect to each other, in accordance with an embodiment of the presentinvention.

FIG. 6 depicts an embodiment in which outer diameter channels of thebushing and the inner diameter channels of the housing are co-locatedwith each other to at least partially co-form a common channel, inaccordance with an embodiment of the present invention.

FIG. 7 depicts an embodiment of the present invention reducing oreliminating the unwanted pressure differential between bushings, inaccordance with an embodiment of the present invention.

The drawings referred to in this description should be understood as notbeing drawn to scale except if specifically noted.

DESCRIPTION OF EMBODIMENTS

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various embodiments of thepresent invention and is not intended to represent the only embodimentsin which the present invention is to be practiced. Each embodimentdescribed in this disclosure is provided merely as an example orillustration of the present invention, and should not necessarily beconstrued as preferred or advantageous over other embodiments. In someinstances, well known methods, procedures, objects, and circuits havenot been described in detail as not to unnecessarily obscure aspects ofthe present disclosure.

As stated above, in some fork assemblies such as, for example, bicycleor motorcycle fork assemblies, an upper fork leg is telescopicallyengaged with a lower fork leg. For purposes of brevity and clarity, thefollowing discussion will refer to a first fork leg and a second forkleg to avoid unnecessarily limiting use of the present embodiments toone or other of the upper fork leg and the lower fork leg. Moreover,embodiments of the present invention are well suited for use in an upperfork leg, a lower fork leg, or concurrently in both of the upper forkleg and the lower fork leg. Furthermore, embodiments of the presentinvention are also used in structures other than fork legs (such as, butnot limited to, struts, seat posts, etc.) in which the use of a bushingis required or desired. That said, for purposes of brevity and clarity,and not to be interpreted as a limitation, the following discussion willrefer to embodiments of the invention pertaining to a fork leg.

Additionally, in the present application, for purposes of brevity andclarity, the following discussion will refer to a “bushing”. It shouldbe noted that the term “bushing”, as used herein, is intended to referto an element (sometimes referred to in the art as a “bushing” andsometimes referred to in the art as a “bearing”, or some other term)which provides an interface between moving parts, such as, but notlimited to, a first fork leg and a second fork leg.

Additionally, embodiments of the present invention are used in a forkleg with a single bushing, and embodiments of the present invention arealso used in a fork leg with two or more bushings. Discussions hereinpertaining to an embodiment with a single bushing may also pertain toembodiments with two or more bushings.

As will be described in detail below, embodiments of the presentinvention provide a bushing bypass. Referring now to FIG. 2, aperspective view of a bushing 200 in accordance with one embodiment ofthe present invention is shown. As shown in FIG. 2, in one embodiment, abushing 200 has a plurality of channels, typically shown as, 202 a, 202b, 202 c and 202 d formed into the outer diameter of bushing 200.Although four channels 202 a, 202 b, 202 c and 202 d are shown in theembodiment of FIG. 2, bushing 200 is also well suited to an embodimentin which bushing 200 has a single channel, and to embodiments in whichbushing 200 has more than a single channel. As shown in FIG. 2, inbushing 200, channels 202 a, 202 b, 202 c and 202 d extend, along theouter diameter of bushing 200, from one side (e.g., the top side) ofbushing 200 to the other side (e.g., the bottom side) of bushing 200. Insuch an embodiment, channels 202 a, 202 b, 202 c and 202 d are formedinto the outer diameter of bushing 200 and have a sufficient depth andshape to allow gases or fluids to flow through the channel and, as aresult, around the outer diameter of bushing 200 and between the innerdiameter of a fork leg housing, when bushing 200 is disposed within thefork leg housing.

Referring still to FIG. 2, although only a single bushing 200 is shownfor purposes of brevity and clarity, in various embodiments, at leastone channel is formed into the outer diameter of two (or more) bushingsin a single fork assembly (or within a single fork leg) to reduce gas orfluid restriction at the location of each of the two (or more) bushings.

Referring now to FIG. 3, a perspective view of a fork leg 300 inaccordance with one embodiment of the present invention is shown. Asshown in FIG. 3, in another embodiment, the present invention iscomprised of a channel 302 formed into the inner diameter of the housingof fork leg 300. Moreover, in such an embodiment, channel 302 is formedinto the inner diameter of the housing at a location where a bushing(such as, but not limited to, for example, bushing 200 of FIG. 2) willreside.

Additionally, in the embodiment of FIG. 3, channel 302 is formed intothe inner diameter of the housing and has a length such that channel 302will extend, at least, from one side of a bushing to the other side ofthe bushing (when the bushing is located in the housing). Again, in suchan embodiment, fork leg 300 will have one or more channels formed intothe inner diameter of the housing of fork leg 300 (FIG. 3 shows anembodiment having only a single channel 302 for brevity and clarity andnot as a limitation). In such an embodiment, channel 302 is formed intothe inner diameter of the housing of fork leg 300 and has a sufficientdepth and shape to allow gases or fluids to flow through the channeland, as a result, around the outer diameter of a bushing when a bushingis disposed within the fork leg housing.

Referring still to FIG. 3, although channel 302 is shown at the locationwhere a single bushing will reside, for purposes of brevity and clarity,in various embodiments, an additional channel (or channels) is formedinto the inner diameter of the housing at other locations where otherbushings will reside. Furthermore, embodiments of the present inventionare well suited to use within a single fork assembly (or within a singlefork leg) to reduce gas or fluid restriction at the location of each ofthe two (or more) bushings.

Referring still to the embodiment of FIG. 3, in another embodiment asingle channel 302 is formed into the inner diameter of the housing withsingle channel 302 having a length sufficient to extend past each of thelocations where two (or more) bushings are disposed within fork leg 300.

Referring now to FIG. 4, in another embodiment, channels 202 a and 202 bare formed into the outer diameter of a first bushing 200 a, andchannels 302 a, 302 b and 302 c are formed into the inner diameter ofthe housing at the location where a second bushing 202 b is disposed toreduce gas or fluid restriction at the location of first bushing 200 aand second bushing 200 b.

Referring now to FIG. 5, in another embodiment, one or more channels 202a and 202 b are formed into the outer diameter of a bushing 200, and oneor more channels 302 a, 302 b and 302 c are formed into the innerdiameter of the housing at the location where bushing 200 is disposed.In such an embodiment, the outer diameter channels 202 a and 202 b onbushing 200 and the inner diameter channels 302 a, 302 b and 302 c onthe housing both reduce gas or fluid restriction at the location of thebushing. In the embodiment of FIG. 5, the outer diameter channels of thebushing and the inner diameter channels of the housing are offset fromeach other such that the bushing outer diameter channels and the housinginner diameter channels do not co-form any common channel.

Referring now to FIG. 6, in the present embodiment, at least one of theouter diameter channels of the bushing and at least one of the innerdiameter channels of the housing can be co-located with each other to atleast partially co-form a common channel.

Referring now to FIG. 7, embodiments of the present invention therebyreduce or eliminate the unwanted pressure differential between bushingsas is found in conventional fork legs. Notice in FIG. 7, that inembodiments of the present invention, the regions on various sides ofbushing 1 and bushing 2 are at the same pressure, pressure 1.Additionally, embodiments of the present invention are able to reduce oreliminate the unwanted pressure differential between bushings withoutnegatively affecting the interface between the inner diameter of abushing and the outer diameter of a fork leg slideably engaged with theinner diameter of the bushing. Hence, embodiments of the presentinvention maintain and protect the integrity of the interface betweenthe inner surface of the bushing and the outer diameter the fork legslideably engaged with the inner diameter of the bushing. It will beunderstood that FIG. 7, represents embodiments in which channels areformed into the inner diameter of a housing. FIG. 7 also representsembodiments in which channels are formed into the outer diameter of abushing. FIG. 7 also represents embodiments in which channels are formedinto the inner diameter of a housing and channels are formed into theouter diameter of a bushing.

In one embodiment, the present bushing bypass is used in a fork whichincludes a self-lubricating suspension seal. A detailed description ofsuch a self-lubricating suspension seal is found in U.S. Pat. No.8,672,096 to Galasso et al., issued Mar. 18, 2014, and entitled “Methodsand Apparatus for Lubricating Suspension Components”, which iscommonly-owned by, and assigned to, the assignee of the presentapplication. The aforementioned U.S. Pat. No. 8,672,096, is hereinincorporated by reference, in its entirety, into the presentapplication. Furthermore, in one embodiment, the present bushing bypassis used in a fork which includes an air bleed assembly. A detaileddescription of such an air bleed assembly is found in U.S. Pat. No.9,739,331 to William M. Becker, issued Aug. 22, 2017, and entitled“Method and Apparatus for an Adjustable Damper”, which is commonly-ownedby, and assigned to, the assignee of the present application. Theaforementioned U.S. Pat. No. 9,739,331, is herein incorporated byreference, in its entirety, into the present application.

The examples set forth herein were presented in order to best explain,to describe particular applications, and to thereby enable those skilledin the art to make and use embodiments of the described examples.However, those skilled in the art will recognize that the foregoingdescription and examples have been presented for the purposes ofillustration and example only. The description as set forth is notintended to be exhaustive or to limit the embodiments to the preciseform disclosed. Rather, the specific features and acts described aboveare disclosed as example forms of implementing the Claims.

Reference throughout this document to “one embodiment,” “certainembodiments,” “an embodiment,” “various embodiments,” “someembodiments,” “various embodiments”, or similar term, means that aparticular feature, structure, or characteristic described in connectionwith that embodiment is included in at least one embodiment. Thus, theappearances of such phrases in various places throughout thisspecification are not necessarily all referring to the same embodiment.Furthermore, the particular features, structures, or characteristics ofany embodiment may be combined in any suitable manner with one or moreother features, structures, or characteristics of one or more otherembodiments without limitation.

What is claimed is:
 1. A fork leg bushing bypass comprising: a bushing,said bushing comprising: a top surface; a bottom surface; an innerdiameter surface extending between said top surface and said bottomsurface; an outer diameter surface extending between said top surfaceand said bottom surface; and a channel formed in said outer diametersurface, said channel extending from said top surface to said bottomsurface, wherein said channel is formed having a sufficient depth andshape to allow fluids to flow through said channel, around said outerdiameter of said bushing, and between an inner diameter of a fork leghousing and said outer diameter of said bushing, when said bushing isdisposed within said fork leg housing.